Two types of plants in Yunnan, Myriopteron extensum and Derris eriocarpa have been found to contain highly sweet-tasting compounds that are at least 25 times sweeter than sucrose, according to researchers from the Kunming Institute of Botany, Chinese Academy of Sciences.

For instance, 12 new sweet-tasting compounds, known as C21 pregnane glycosides, were found in the roots of Myriopteron extensum, ​a plant commonly used by the Yao minority as food and medicine.

Out of the 12 compounds, nine are highly sweet-tasting compounds which are 25 to 400 times sweeter than sucrose. As compared to the pericarps, the types of sweet-tasting compounds found in the roots were different.

Besides the roots, researchers had previously studied the pericarps of the plant and found it contained 10 new types of sweet-tasting compounds that were 50 to 400 times sweeter than sucrose.

Commenting on the study of the roots, the researchers said that “​the quantitation of the sweet compounds in the pericarps, stems, and roots indicated that all of them contain these kinds of sweet components with a distinct distribution.”​

Analysis also indicated that the concentrations of these sweet components in the pericarps are higher than those in the stems and roots.

As for Derris eriocarpa, ​a plant which the Bourau and Dai minorities believe to exhibit medicinal properties, was found to contain four sweet-tasting compounds (triterpenoid saponins).

Two of these compounds were 150 and 80 times sweeter than sucrose.

This is the first scientific study that investigates the sweetening properties of the two plants.

The researchers added that the study helps “provide a theoretical basis for the rational design and development of natural high-potency and non-sugar sweeteners.”​

At present, monk fruit and Stevia rebaudiana are some examples of natural sweeteners available in the market.

Israel firm Amai Proteins has also developed computerised ‘designer’ sweet proteins​ that mimic those that exist naturally in fruits as a sugar alternative. The sweet proteins are hundreds to a thousand times sweeter than sugar.

Methods​

After the sweet-tasting components in the plants were identified via phytochemical study and spectroscopic technologies, human sensory evaluation was conducted to determine the level of sweetness of the compounds.

As such, a taste panel was formed using the Givaudan’s panelist selection procedure (taste intensity ranking test).

Common uses​

According to the researchers, the two plants are consumed by minorities in Yunnan as both fruit and medicine.

For Myriopteron extensum​, its fruit is usually marinated and consumed as salted vegetable, while its roots have medicinal properties, such as reducing inflammation, promoting respiratory tract health and even treating tuberculosis.

On the other hand, Derris eriocarpa ​is mostly consumed as a drug and reduces phlegm and water retention, and promotes blood circulation.

Source: Journal of Agriculture and Food Chemistry​

DOI: 10.1021/acs.jafc.8b02348

New Sweet-Tasting C21 Pregnane Glycosides from the Roots of Myriopteron extensum​